astro-pure/schemas/favicon.ts

A simple, clean but powerful blog theme build by astro.

import { extname } from 'node:path'
import { z } from 'astro/zod'

const faviconTypeMap = {
  '.ico': 'image/x-icon',
  '.gif': 'image/gif',
  '.jpeg': 'image/jpeg',
  '.jpg': 'image/jpeg',
  '.png': 'image/png',
  '.svg': 'image/svg+xml'
}

export const FaviconSchema = () =>
  z
    .string()
    .default('/favicon/favicon.svg')
    .transform((favicon, ctx) => {
      // favicon can be absolute or relative url
      const { pathname } = new URL(favicon, 'https://example.com')
      const ext = extname(pathname).toLowerCase()

      if (!isFaviconExt(ext)) {
        ctx.addIssue({
          code: z.ZodIssueCode.custom,
          message: 'favicon must be a .ico, .gif, .jpg, .png, or .svg file'
        })

        return z.NEVER
      }

      return {
        href: favicon,
        type: faviconTypeMap[ext]
      }
    })
    .describe(
      'The default favicon for your site which should be a path to an image in the `public/` directory.'
    )

function isFaviconExt(ext: string): ext is keyof typeof faviconTypeMap {
  return ext in faviconTypeMap
}